The benefits of regular aerobic exercise are well established. However, due to time constraints, inclement weather, and other reasons, many people are prevented from aerobic activities such as walking, jogging, running, and swimming. In response, a variety of exercise equipment has been developed for aerobic activity. It is generally desirable to exercise a large number of different muscles over a significantly large range of motion so as to provide for balanced physical development, to maximize muscle length and flexibility, and to achieve optimum levels of aerobic exercise. It is further advantageous for exercise equipment to provide smooth and natural motion, thus avoiding significant jarring and straining that can damage both muscles and joints.
While various exercise systems are known in the prior art, these systems suffer from a variety of shortcomings that limit their benefits and/or include unnecessary risks and undesirable features. For example, stationary bicycles are a popular exercise system in the prior art; however, these machines employ a sitting position that utilizes only a relatively small number of muscles, through a fairly limited range of motion. Cross-country skiing devices are also utilized to simulate the gliding motion of cross-country skiing. While cross-country skiing devices exercise more muscles than stationary bicycles, the substantially flat shuffling foot motion provided by the ski devices limits the range of motion of some of the muscles being exercised. Another type of exercise device simulates stair climbing. These devices exercise more muscles than stationary bicycles; however, the rather limited range of up-and-down motion utilized does not exercise the leg muscles of the user through a large range of motion. Treadmills are still a further type of exercise device in the prior art. Treadmills allow natural walking or jogging motions in a relatively limited area. A drawback of the treadmill, however, is that significant jarring of the hip, knee, ankle and other joints of the body may occur through use of this device.
A further limitation of a majority of exercise systems in the prior art lies in the limits in the types of motions that they can produce. Relatively new classes of exercise devices are capable of producing elliptical motion. Exercise systems create elliptical motion, as referred to herein, when the path traveled by a user's feet while using the exercise system follows a generally arcuate or ellipse-shaped path of travel. Elliptical motion is much more natural and analogous to running, jogging, walking, etc., than the linear-type, back and forth motions produced by some prior art exercise equipment.
An initial drawback of such elliptical trainers was that the step height or angle from horizontal of the elliptical path that the feet traveled during use was fixed. Thus, such trainers provided only a single exercise motion that exercised only certain muscle groups. This drawback was solved by the use of an adjustable guide with which the user could adjust the angle of the elliptical path that the feet traveled relative to horizontal, thereby enabling different elliptical exercise motions to be used and different muscle groups to be exercised during use.
Another initial drawback of such elliptical trainers was that devices only exercised the lower part if the body. This drawback was solved by exercise devices that provide arm, shoulder, and general upper body motions as well as elliptical foot motions. These prior art devices utilize arm and shoulder motions that are linked to foot motions, where the motions of the feet of a user are linked to the motions of the arms and shoulders. One drawback to these linked devices is that, because of the complexity and geometry of the mechanism used to link the motions of the arms and shoulders to the foot motion, an adjustable guide with which the user could adjust the step height, or the angle of the elliptical path that the feet traveled relative to horizontal, could not be used without resulting in binding of the linkage or an undesirable arm and shoulder motion. Accordingly, existing elliptical exercise devices have not incorporated an adjustable ramp or guide with structure for arm, shoulder and upper body motion.
Another drawback to these linked devices lies in the desire of certain users to utilize the foot motions without a corresponding utilization of the arm apparatuses. Because the arm apparatuses travel through a given path regardless of whether the user is exerting any force on the arm apparatus, many users find the back and forth motion of the arm apparatuses to be bothersome and distracting when the user does not wish to engage the arm apparatuses.
What would thus be desirable is an exercise device that provides for smooth natural action, and exercises a relatively large number of muscles through a large range of motion. It would be further desirable for an exercise device to employ a natural, desirable arm, shoulder, and upper body movement in association with the ability to enable the user to vary the step height, or the angle of the elliptical path that the feet traveled relative to horizontal, of the exercise device. It would be further desirable for an exercise device to further allow a user to easily and efficiently choose to use or not to use the arm apparatus.